Answer:
morphemes.
Step-by-step explanation:
A morpheme can be defined as the smallest and meaningful unit in linguist that can not be further divided.
For example, apple is a morpheme, and if added 's' then the word apples will have two morpheme 'apple' and '- s.'
In the given example, the word tricycle is the combination of two words 'tri' which means 'three' and 'cycle.' The word 'tri' is a prefix used to word a word tricycle which means that the object has three wheels.
This prefix 'tri' is an example of morpheme. And '-s' is also an example of morpheme.
So, the correct answer is morpheme.